Add typechecking

[vthemelis]

This only really adds pyright to tox and ignores to everything that's flagged.

The ignores can be incrementally removed.

[tobgu]

Thanks!

When adding # type: ignore[reportGeneralTypeIssues] like done in this PR, there is no risk that type checkers in editors start ignoring things they previously reported errors on?

What are the errors being reported, that we ignore?

[vthemelis]

Hi @tobgu,

reportGeneralTypeIssues is a pyright error type. I'm just disabling it on lines that were flagged for now instead of fixing. I find that this is an easy way to incrementally add type checking into a project. You could fix the error when you're next in the area but in the meantime, pyright will avoid more type errors appearing in the codebase.